The present invention relates to a process for the production of at least one high-pressure gaseous fluid which comprises fluid selected from the group consisting of oxygen and nitrogen, by cryogenic air separation, said fluid being pumped in a liquid state to an elevated pressure, then vaporized and reheated at an elevated pressure in a heat exchanger.
In this specification, the term "high pressure" means a pressure which is greater than about 15 bar for oxygen and a pressure which is greater than about 30 bar for nitrogen. The term "blower" means a compressor having a compression ratio of less than about 2. The term "cold blower" means a blower operating at an inlet temperature of less than about minus 40.degree. C. Furthermore, any pressure referred to herein is an absolute pressure.
The processes disclosed in the art relating to the production of oxygen by the so-called "pump processes" have some advantageous features; such as avoiding the use of product oxygen compressor which is usually very expensive, unreliable and gives a very poor yield.
However, in order to use the previously described liquid "pump processes", an operator must attempt to balance the excess of cold brought about by the vaporization of product fluid, and to bring a sufficient quantity of an exchange fluid in heat exchange relationship with the product fluid, said exchange fluid being capable of condensing at about the vaporization temperature of the product fluid, or alternatively which exchange fluid heat capacity is sufficient at this temperature.
The exchange fluid characteristic requirements are thus a significant limitation to the possible use of the so-called "pump processes", particularly when the production pressure of oxygen is high, i.e. greater than about 15 bar. For example, for an oxygen pressure greater than about 15 bar, it would be necessary to compress to a high pressure a flow of air or nitrogen which is at least equal to 150% of the oxygen flow, which is impractical and expensive in terms of energy.
A process and installation to effectively carry out the production of high pressure gaseous fluid from a liquid would be advantageous and is much desired.